I believe splenda is made is chlorinated sucrose made with thionyl chloride and one of the more basic amines. The reaction would most likely be quenched with water, destroying any unreacted thionyl chloride, which is really the only chemical to worry about. Thionyl chloride breaks down to sulfur dioxide and hydrochloric acid. The S02, a gas, is not present simply becuase its a dry product. HCl would be washed out with the quench, which would also remove the amine since it is going to be in salt form with the HCl (unless it is an amine with a large enough molecular weight). Any trace chlorine would be in the form of the chloride in the acid. Just for reference HCl is the major consituent of stomach acid.
If I am correct in the way it is made, of which I am confident, I personally have no worries.